A failure occurring in a SCP of an intelligent network element or interruption of communication between a MSC and the SCP will cause users under the SCP to be unable to make calls, bringing losses to operators. In order to overcome this problem, a method for calculating bypass SCP of a called user is proposed in the field. In this method, the status or communication situation of the SCP is determined before interaction with the SCP, if it is normal, the current call connection triggers normally a trigger to the SCP, if it is abnormal, the call connection does not trigger the trigger, and connect the user as a non-intelligent user. Fees are accounted, compensated and deducted according to a bill output by the MSC to minimize losses of the operators and improve customer satisfaction.
In a Code Division Multiple Access (CDMA) mobile telecommunication network, a intelligence trigger of a called user triggers two MSCs, first a gateway office—a Gateway Mobile Switching Center (GMSC) which is a MSC that initiates a location request of the called user (and also has the function of a Service Switch Point (SSP)), and then a end office—a Visited Mobile Switching Centre (VMSC) which is a MSC in which the current location of the called user is located. Therefore, intelligent services of the called user may be bypassed because of failures of communication between the GMSC and a SCP of the called user, and if the communication between the GMSC and the SCP is normal, the intelligent services of the called user will not be bypassed, the call thus will still fail. Conversely, if the SCP are not bypassed in the GMSC and the SCP is bypassed in the VMSC, the call will fail as well.
A specific scenario where a call failure is caused when the GMSC and the VMSC are not the same MSC and situations as to whether the intelligent services of the called user are bypassed are different in the GMSC and the VMSC will be described in detail below by taking primary-backup disaster recovery of a MSC as an example. Of course, such a problem is not limited to be caused by the primary-backup disaster recovery, it may exist in various disaster recoveries of the MSC.
FIG. 1 is a structural diagram of an intelligent network of a CDMA mobile network. Normally, when a MSC discovers that a user is an intelligent user, it needs to interact with a SCP when connecting a call of the user. An intelligent trigger list of the called user is obtained from a Home Location Register (HLR) by registration, qualification indication or qualification request. The intelligent trigger list of the called user may be obtained in another way, that is, it is obtained by a gateway office through a location request.
FIG. 2 illustrates a flowchart of a process of how an end office VMSC obtains an intelligent trigger list of q called user.
In S201, a Mobile Station (MS) initiates a location updating request to a Base Station Controller (BSC).
In S202, the BSC receives the location updating request and then sends it to a MSC in which the called user is located, i.e., the VMSC.
In S203, the VMSC returns a location updating response to the BSC after receiving the location updating request of the BSC.
In S204, the BSC receives the location updating response and then sends it to the MS.
In S205, if the VMSC needs to send registration (change in the location of the MS is great or start-up registration) to a HLR, the VMSC sends a registration request to the HLR.
In S206, the HLR receives the registration request, updates user information, and returns a register response carrying the intelligent trigger list of the called user to the VMSC.
Referring to FIG. 3 below, which illustrates a case where the existing gateway office GMSC and end office VMSC are not the same MSC and the gateway office GMSC determines that intelligent services of a called user are not required to be bypassed and the end office VMSC determines that the intelligent services of the called user are required to be bypassed.
In S301, a front office sends a call request to the gateway office GMSC.
In S302, the GMSC receives the call request and then sends a location request to a HLR.
In S303, the HLR receives the location request, queries user information contained in the location request, and returns a location response carrying an intelligent trigger list of the called user to the gateway office GMSC when discovering that the user is an intelligent user.
In S304, the gateway office GMSC receives the location response, finds the intelligent trigger list of the called user, determines that the intelligent services of the called user are not required to be bypassed according to the intelligent trigger list of the called user (e.g., whether failures occur in a corresponding SCP), and sends an initial terminal trigger to the SCP.
In S305, the gateway office GMSC receives an initial terminal trigger response returned by the SCP.
In S306, the gateway office GMSC sends a location request to the HLR, wherein the trigger is a location trigger.
In S307, the HLR sends a routing request to the end office VMSC.
In S308, the end office VMSC returns a routing request response to the HLR.
In S309, the HLR returns a location request response carrying routing information of the called user to the gateway office GMSC.
In S310, the gateway office GMSC sends a routing address available trigger of the called user to the SCP.
In S311, the SCP sends a routing address available trigger response to the gateway office GMSC.
In S312, the gateway office GMSC receives the routing address available trigger response from the SCP and then analyses a number to obtain routing of the corresponding service MSC, and sends a call request to the end office VMSC.
In S313, the end office VMSC receives the call request and finds that the called user is a local office user and is an intelligent user, continues to determine whether the intelligent services of the called user are required to be bypassed in the VMSC, if they are required to be bypassed, the end office VMSC connects the called user, and when the called user is ringing, the end office VMSC sends the ringing to the gateway office GMSC.
In S314, the gateway office GMSC forwards the ringing to the front office.
In S315, the called user answers, and the end office VMSC sends an answer to the gateway office GMSC.
In this step, the answer sent by the end office VMSC to the gateway office GMSC corresponds to an answer to a call request sent by the gateway office GMSC to the end office VMSC.
In S316, the gateway office GMSC forwards the answer to the front office, and a calling user and the called user begin to talk.
In S317, because the SCP does not receive an answer trigger for a long time, it sends a message to the GMSC to indicate to release the call.
The step S317 is also the reason for failure of the call in the case where the gateway office GMSC and the end office VMSC are not the same MSC and the intelligent services of the called user are not bypassed in the gateway office GMSC and the intelligent services of the called user are bypassed in the end VMSC. That is to say, because the intelligent services of the called user at the SCP are triggered in the gateway office GMSC and the intelligent services of the called user are required to be bypassed in the VMSC, the answer trigger cannot be returned to the SCP such that the SCP believes that an error occurs and releases the call because it does not receive the answer trigger for a long time.
In S318, the gateway office GMSC sends a release call message to the front office.
In S319, the gateway office GMSC sends a release message to the end office VMSC.
Then referring to FIG. 4 below, which illustrates a case where the existing gateway office GMSC and end office VMSC are not the same MSC and the gateway office GMSC determines that intelligent services of a called user are required to be bypassed and the end office VMSC determines that the intelligent services of the called user are not required to be bypassed.
In S401, a front office sends a call request to the gateway office GMSC.
In S402, the GMSC receives the call request and then sends a location request to a HLR.
In S403, the HLR receives the location request, queries user information contained in the location request, and returns a location response carrying an intelligent trigger list of the called user to the gateway office GMSC when discovering that the user is an intelligent user.
In S404, the gateway office GMSC receives the location response, finds the intelligent trigger list of the called user, determines that the intelligent services of the called user are required to be bypassed according to the intelligent trigger list of the called user (e.g., whether failures occur in a corresponding SCP), and sends the location request to the SCP, wherein the trigger is a location trigger.
In S405, the HLR sends a routing request to the end office VMSC.
In S406, the end office VMSC returns a routing request response to the HLR.
In S407, the HLR returns a location request response carrying routing information of the called user to the gateway office GMSC.
In S408, the gateway office GMSC sends a call request to the end office VMSC.
In S409, the end office VMSC receives the call request and finds that the called user is a local office user and is an intelligent user, continues to determine whether the intelligent services of the called user are required to be bypassed in the VMSC, if they are not required to be bypassed, the end office VMSC connects the called user, and when the called user is ringing, the end office VMSC sends the ringing to the gateway office GMSC.
In S410, the gateway office GMSC forwards the ringing to the front office.
In S411, the called user answers, and the end office VMSC sends an answer to the SCP.
In S412, the end office VMSC sends an answer to the gateway office GMSC.
In S413, the gateway office GMSC forwards the answer to the front office, and a calling user and the called user begin to talk.
In S414, because the SCP has not received a trigger previously and received directly the answer, it may believe that an error occurs and send a release indication to the end office VMSC.
The step S414 is just the reason for failure of the call in the case where the gateway office GMSC and the end office VMSC are not the same MSC and the intelligent services of the called user are bypassed in the gateway office GMSC and the intelligent services of the called user are not bypassed in the end VMSC. That is to say, because the intelligent services of the called user are bypassed in the gateway office GMSC and the intelligent services of the called user are not triggered and the end office VMSC triggers the intelligent services of the called user and returns an answer trigger to the SCP such that the SCP receives the answer directly without receiving the trigger and determines that an error occurs and releases the call.
In S415, the gateway office GMSC sends a release call message to the front office.
In S416, the gateway office GMSC sends a release message to the end office VMSC.
Deficiencies in above FIG. 3 and FIG. 4 are not limited to be caused by primary-backup disaster recovery, they may exist in various disaster recoveries of the MSC. Currently, there is no corresponding solution to the problem that call failure is caused when the GMSC and the VMSC are not the same MSC and situations as to whether the intelligent services of the called user are bypassed are different in the GMSC and the VMSC.